Bow for archery



" May 29, 1934.l R, H CQWDERY 1,960,478

BOW FOR ARCHERY Filed May 19, 1930 eil , his azaz" 5y Patented May 29, 1934 PATENT OFFICE l i BOW FOR ARCHERY l Robert H. Cowdery, Geneva, Ohio, assignor to The American Fork & Hoe Company, Cleveland, Ohio, a corporation of Ohio Y Application May 19, 1930, serial No. 453,591

9 Claims.

My invention relates to bows for archery and relates particularly to metallic bows.

In my co-pending application, Serial No. 211,- 326, filed August 8, 1927, I have disclosed an archers bow of tubular steel construction, wherein, however, the wall thicknesses of the limbs of the bow are progressively increased proceeding from the paradox, or handlegrip portion, towards the tips.

I now nd that for most purposes a superior bow will be provided if the thickness of wall is not increased proceeding from the handle towards the tips, and the beneficial effect is enhanced if the thickness of wall be actually decreased proceeding toward the tips, as the diameters of the portions are decreased. Bows so formed have a rapidity of response in their tip portions which is in excess of that attainable in other constructions with which I am familiar.

Such a bow is particularly desirable for target purposes wherein a relatively light arrow is used.

An object of my invention is to provide a tubular bow wherein Athe rapidity of response by the tip portions is increased over the tip portions of` other tubular bows with whichI am familiar. l

Another vobject of vmy invention is to provide as a further feature of improvement, a metallic tubular bow especially adapted for efficient target shooting. y Y 1 Another object of my invention is to provide an improved tubular metallic bow tapered toward its two ends. K

Another object of my invention is to provide a metallic bow which will be eflicient in operation and which will resist breakage to a degree previously unknown for tubular bowsy of the same pull and power.

Another object of my invention is to provide an improved process for making bows.

Other objects of my invention comprise of improvements in tubular bows hereinafter described and claimed, and which will become more apparent from the following description, in which reference will be made to the accompanying drawing forming a part of this specification.

Referring to the drawing:

Fig. 1 is a view in side elevation of a bow ernbodying the principles of my invention;

Fig. 2 is a longitudinal medial sectional View of the bow of Fig. 1*;

Figs. 3, 4, 5 and 6 are transverse sections taken on the lines 3 3, 4 4, 5-5and 6-6, respectively, of Fig. 1; and

Fig. 7 is a. longitudinal medial sectional view of a die which may be used in forming the bow of my invention.

Referring to the figures of drawing, in all of which like parts are designated by like reference characters, at 1, I show an upper limb and at 2, I show a lower limb of a bow. The limbs are joined together at their larger ends by telescoping both limbs into opposite ends of a metallic tube 4, the ends of the bow limbs meeting in the center of the tube, and preferably one of the bow limbs, such as the limb 2, will be soldered or otherwise tightly secured within the tube so as to prevent removal therefrom. The upper limb will be Va pressed fit into 4the tube, from whence it may be removed by a strong'pull in order to reduce the length of the package in which such a bow may be placed when carrying it. A suitable hand grip covering 5 will be placed over the tube 4 and is preferably glued thereon. Such a covering may be made of cork, felt, leather, a strip of velvet, or other soft material in the form of a strip, wound or telescoped over the tube and glued securely thereto.

The limbs 1 and 2, as clearly shown in Fig. 2, are tubular in form and the walls are made progressively thinner proceeding from the enlarged joined ends. The tips, as shown at 5',

are relatively small in diameter and have relative- -ly thin walls.

In practice, preferably, the thickness of wall may be progressively varied so that, for instance, the wall thickness at the tips will be only of the wall thickness at the joined larger ends of the bow, and I preferably make the bow limbs of such a form as illustrated, wherein the concave `form is produced by the backs of the two joined limbs when the bow is unstrung, producing what is known as a reflexed bow. However, the bow may be made in the ordinary convex form throughout its length, within the purview of my invention.

I preferably form the limbs 1 and 2 each from a like straight tube having initially in all portions the same diameter of the finished tube at its larger end, that is substantially equal to the inside diameter of the handle tube 4. The tube is then progressively reduced, in diameter, and in its wall thickness, by telescoping a mandrel corresponding in form to the interior of the iinished tube desired, into the straight tube and then by a spinning process, rolling downwith tremendous pressure, the material of the straight tube on to the tapered mandrel, proceeding preferably from the enlarged'end to the small end of the tube.

Although this may be done in various ways, I preferably spin the tube by the use of the apparatus illustrated generally in Fig. 7 and wherein a hardened camming ring 6 is provided, rotatably mounted in a support 7, radially disposed bearing balls 8 being interposed between the supporting ring and the camming ring 6. The ring 6 has an interior wall 9 of frusto-conical form, being tapered longitudinally of its axis. Another set of bearing balls 13 is interposed between an end of the ring and an end wall 15 of the holder 7. A set of hardened die balls 17 is interposed between the tube 10 to be operated upon and the inner tapered surface 9 of the ring 6.

In spinning a tube, the tube with the mandrel 14 within it is clamped by its larger end within the jaws 16 of a collet, rotatable preferably by an electric motor or the like. The collet and the operating motor therefor is adapted to be moved longitudinally of the die head, comprising the ring 6V and the die balls 17, and associated parts, in the direction of the arrow, and at the same time, the tubular cage 18, through openings 19 of which the die balls project, is moved axially of the tube 10and tapered ring 6 in a direction opposite to that indicated by said arrow, whereby the die balls 17 engaging the inclined surface 9 of the ring are forced inwardly gradually while the tube 10 and mandrel 14 are together rotated at a high rate of speed, such as 3000 revolutions per minute, and at the same time longitudinally in the direction of the arrow.

'I'he mechanism just described comprising the spinning die is not a part of my own invention but is described and claimed in a co-pending application of James L. Cassady, Serial No. 652,256 filed Jan. 18, 1933, to which reference may be had for a fuller description thereof. I und, however, that this mechanism when employed in connection with a suitably formed tapered surface 9 and a suitablyl formed mandrel 14 may be manipulated `to effect a reduction in the wall thickness of the tapered tube which results from the operation described. This is done by suitably predetermining that, as the balls 17 move toward the end'of the ring 6 thrusting against the bearings 13, there will be progressively less and less space provided between such die balls 17 and the mandrel 14 disposed interiorlyof the tube 10.

The mechanism for advancing the die ball cageV 18 longitudinally of the ring 6, within the ring, is not shown herein, reference being had to the said Cassady co-pending application for a complete description thereof. It is sufficient for the present case that the movement of the cage 18 is proportional to the movement of the mandrel 14 and the tube 10 and made so by suitable gearing connections interposed therebetween. Y

The longitudinal movement thus given to the ball cage 18 relative to the ring 6 is in the present embodiment accomplished at such a rate relative to the rate of taper of the mandrel 1 4 that as the tube 10 is moved longitudinally in the direction of the arrow, that the balls 17 are moved inwardly toward the axis of the mandrel along the tube inner walls 19 of the ring at a rate which will provide gradually less and less spacing between the inner surfaces of the balls and the outer surface mandrel, while the mandrel with the tube is being withdrawn through-the throat of Ythe die comprising the die balls.

This is while the mandrel and tube is being rotated at a very high. rate of speed such as 3000 revolutions per minute and which produces terial. The bow ends thus formed are then given a'suitable rust proof coating or lacquer or the like and then forced into the handle tube 4.

I iind that a bow constructed as above described and having, for instance, wall thicknesses varying from .020 inch at the larger ends of the bow limbs down to .012 in portions adjacent the tips, when made 0f tempered steel material, as described, are extremely live and do not have the loggy quality which is especially undesirable in bows intended for archery practice Wherein light arrows are used. V

I-Iaving thus described my invention in a specic embodiment, I am aware that extensive and numerous departures may be made from the particular form of embodiment herein illustrated but within the purview of my invention.

I claim:

1. A metallic tubular bow enlarged in its mid portion and of gradual decreasing diameter and decreasing wall thickness in portions progressive- .ly nearer its tips.

. 2. A metallic tubular bow having a mid portion of maximum diameter and decreasing gradually in diameter progressively toward its tips, and having tubular walls of a thickness in the portions of larger diameter not exceeded by the wall thickness of tubular portions relatively nearer the tips.

Y 3. A metallic tubular bow relatively large in its mid portion and of gradually decreasing diameter in portions progressively near its tips, and having tubular walls of a thickness, in the portions of larger diameter'greater than the wall kthickness of tubular portions relatively nearer the tips. A

. 4. A metallic tubular bow enlarged in its mid portion and of gradual decreasing diameter and decreasingwall thickness in portions progressively nearer its tips, and a relatively soft hand grip applied to the enlarged portion of the bow, and

means rigidly secured to the tubular portion of ameter, each of said limbs having tubular walls "f in their portions of largest diameter thicker than the walls in portions relatively nearer the tips.

7. In a metallic tubular bow, a pair ofoppositely extending bow limbs therefor of progressively less and less diameter toward their tips, l

each of said limbs having tubularwalls in por.- tions of larger diameter thickerthan the walls in their portions relatively nearer the tips commensurable with the increase in diameter.

`8. In a metallic tubularbow, a pair ofoppositely extending bow limbs therefor of progressively less and less diameter toward their tips, each of said limbs having tubular Walls in portions of larger diameter thicker than the Walls in their portions relatively nearer the tips substantially proportional With the increase in diameter.

ROBERT H. COWDERY. 

